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      STACKER NOTE                                         STACKER NOTE
                          IBM-DOS 6.1 HANGS AT SWAP
                          (Applies to Stacker 4.0)
      STAC FAX  4307 (05-27-1994)
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      BACKGROUND
      
      Early releases of IBM's PC-DOS 6.1 may sometimes hang during
      start up when the Stacker drives are swapped. Experience
      indicates that this only occurs if PC-DOS does not support
      preloading compression drivers. The actual hang happens when the
      Stacker command SSWAP.COM is executed from the CONFIG.SYS file.
      In many cases this condition can be corrected by inserting or
      moving a SHELL statement in relation to the SSWAP.COM line in
      CONFIG.SYS.
      
      SOLUTION
      
         - Determine if your version of PC-DOS supports preloading
         - Modify the CONFIG.SYS file to prevent the error
           
      Determine if your version of PC-DOS supports preloading
      
      You may determine if your version of PC-DOS supports preloading
      compression drivers in two ways: first, view the DOS startup
      message. Second, examine the CONFIG.SYS file for the Stacker
      lines.
      
       1.  During startup, most computers give a diagnostic beep. Just
           after this beep, the DOS startup message appears. The
           message "Starting xx-DOS" is displayed on the screen. If the
           message is "Starting IBM DOS", preloading is not supported.
           If the message is "Starting PC DOS", preloading is
           supported.
       2.  Examine the CONFIG.SYS file by typing ED /C <enter> at the
           DOS prompt. Locate the Stacker lines near the end of the
           file. Non-preloading Stacker lines look something like this:
           DEVICE=C:\STACKER\STACKER.COM
           DEVICE=C:\STACKER\SSWAP.COM
           The combination to look for is the message "Starting IBM
           DOS" and the Stacker lines above.
           
      Modify the CONFIG.SYS file to prevent the error
      
       1.  To boot without swapping drives and hanging, press and hold
           both SHIFT keys after the system beeps. When you see the
           message whether to swap the drives, release the SHIFT keys
           and respond "no".
       2.  Open the CONFIG.SYS file in an editor. Locate the
           line that begins "SHELL=...". If the line does not exist,
           insert it after Stacker's SSWAP.COM line. If the line does
           exist, move it to the other side of the SSWAP.COM line. For
           example:
           a. If the SHELL statement did not exist, or is placed before
           the Stacker lines, insert or move the SHELL statement so
           that it appears in this order:
           DEVICE=C:\STACKER\SSWAP.COM
           SHELL=C:\DOS\COMMAND.COM C:\DOS /P
           b. If the SHELL statement appears after the Stacker lines,
           move it to before the Stacker lines so that they appear in
           this order:
           SHELL=C:\DOS\COMMAND.COM C:\DOS /P
           DEVICE=C:\STACKER\STACKER.COM
           DEVICE=C:\STACKER\SSWAP.COM
           Your SHELL statement may have different or additional
           parameters. See your DOS documentation for details on the
           SHELL statement.
       3.  Save the changes to the file by pressing CTRL-Z. Restart
           your system. It should start normally.
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      Copyright 1994 Stac Electronics
